guilt offering: See study note on 1 Samuel 6:3.
Ashdod, Gaza, Ashkelon, Gath, and Ekron: These were the five main Philistine cities. They were on or near the Great Trunk Road, an important ancient trade route. This route connected Egypt with Mesopotamia through the coastal plain of Canaan. Each city had a ruler similar to a king (1 Samuel 6:16).